Change in total glomalin content related to soil proteins after a wildfire in an Andisol of Araucaria araucana forests of south-central Chile

Abstract

In high-altitude montane forests, the vascular plants undergo mycorrhizal symbiosis with mycorrhizal fungi as a strategy to face extreme soil and climate conditions. In this study, glomalin content related to soil proteins (GRSP) was studied, an insoluble glycoprotein produced by hyphae of arbuscular mycorrhizal fungi and deposited on the soil, four years after a wildfire of variable severity, in Araucaria araucana forest in south-central Chile (38° S). For the previously stated, the aim proposed was to determine the content of this glycoprotein as well as to evaluate and relate the composition of soil organic matter to the content of this glycoprotein. Samples were collected at different depths (0-5, 5-10, 10-20 and 20-30 cm, respectively) from areas presenting various fire severities (low, medium and high) and an unburned soil area (control soil). Furthermore, composition and structure of soil organic matter was studied by Nuclear Magnetic Resonance Spectroscopy of ¹³C (NMR ¹³C). As main results, total GRSP concentration showed significant differences between the burned soil and the control soil. A significant correlation between the composition of the organic matter and GRSP was found. The high concentration of GRSP obtained in burned forests could answer to an ecological-evolutionary strategy from the Araucaria araucana forest in their adaptation to both a soil with low nutrient availability and to periodical fire catastrophic events; suggesting their key role in the recovery of these ecosystems and should be considered in restauration programs.